Surface state monitoring method and apparatus

Abstract

The surface state monitoring apparatus comprises: a wafer cassette holding a plurality of semiconductor wafers; an incidence optical system for applying infrared radiation to at least one of said plurality of semiconductor wafers; a detection optical system for detecting the infrared radiation which has undergone multiple reflection in the semiconductor wafer and exited from the semiconductor wafer; surface state monitoring means for monitoring surface states of the semiconductor wafer, based on the infrared radiation detected by the detection optical system; and displacing means for displacing the wafer cassette relative to the incidence optical system and the detection optical system. Surface states of said plurality of semiconductor wafers are sequentially monitored while the wafer cassette is displaced relative to the incidence optical system and the detection optical system by the displacing means, whereby surface states of said plurality of semiconductor wafers held in the wafer cassette are continuously monitored.

What is claimed is:  
     
       1. A surface state monitoring apparatus comprising: 
       a wafer cassette holding a plurality of semiconductor wafers;  
       an incidence optical system for applying infrared radiation to at least one of said plurality of semiconductor wafers;  
       a detection optical system for detecting infrared radiation which has undergone multiple reflection in the semiconductor wafer and exited from the semiconductor wafer;  
       surface state monitoring means for monitoring surface states of the semiconductor wafer, based on the infrared radiation detected by the detection optical system; and  
       displacing means for displacing the wafer cassette relative to the incidence optical system and the detection optical system,  
       surface states of said plurality of semiconductor wafers being sequentially monitored while the wafer cassette is displaced relative to the incidence optical system and the detection optical system by the displacing means, whereby surface states of said plurality of semiconductor wafers held in the wafer cassette are continuously monitored.  
     
     
       2. A surface state monitoring apparatus comprising: 
       a wafer cassette holding a plurality of semiconductor wafers;  
       an incidence optical system for applying infrared radiation to at least one of said plurality of semiconductor wafers;  
       a detection optical system for detecting infrared radiation which has undergone multiple reflection in the semiconductor wafer and exited from the semiconductor wafer; and  
       surface state monitoring means for monitoring surface states of the semiconductor wafer, based on the infrared radiation detected by the detection optical system,  
       the incidence optical system being controlled to apply the infrared radiation sequentially to said semiconductor wafers, whereby surface states of said plurality of semiconductor wafers held in the wafer cassette being continuously monitored.  
     
     
       3. A surface state monitoring apparatus comprising: 
       a wafer cassette holding a plurality of semiconductor wafers;  
       an incidence optical system for applying infrared radiation to at least two or more of said semiconductor wafers;  
       a detection optical system for collectively detecting infrared radiations which have undergone multiple reflection in the semiconductor wafers and exited from the semiconductor wafers, respectively; and  
       surface state monitoring means for monitoring surface states of the semiconductor wafers, based on the infrared radiations detected by the detection optical system.  
     
     
       4. A surface state monitoring apparatus according to  claim 2 , further comprising: 
       displacing means for displacing the wafer cassette relative to the incidence optical system and the detection optical system.  
     
     
       5. A surface state monitoring apparatus according to  claim 3 , further comprising: 
       displacing means for displacing the wafer cassette relative to the incidence optical system and the detection optical system.  
     
     
       6. A surface state monitoring method comprising: applying infrared radiation to at least one of a plurality of semiconductor wafers held in a wafer cassette, detecting infrared radiation which has undergone multiple reflection in the semiconductor wafer and exited from the semiconductor wafer, and analyzing the detected infrared radiation to monitor surface states of the semiconductor wafer, 
       surface states of the semiconductor wafer being monitored while the wafer cassette is displaced relative to an infrared radiation optical system to continuously monitor surface states of said plurality of semiconductor wafers held in the wafer cassette.  
     
     
       7. A surface state monitoring method according to  claim 6 , wherein 
       the wafer cassette is intermittent displaced wafer by wafer relative to the infrared radiation optical system.  
     
     
       8. A surface state monitoring method according to  claim 6 , wherein 
       the wafer cassette is continuously displaced relative to the infrared radiation optical system.  
     
     
       9. A surface state monitoring method according to  claim 8 , wherein 
       a displacement of the wafer cassette relative to the infrared radiation optical system, and a monitor of surface states of the semiconductor wafer are synchronized with each other.  
     
     
       10. A surface state monitoring method according to  claim 6 , wherein 
       a displacement of the wafer cassette relative to the infrared radiation optical system, and a monitor of surface states of the semiconductor wafer are synchronized with each other.  
     
     
       11. A surface state monitoring method according to  claim 7 , wherein 
       a displacement of the wafer cassette relative to the infrared radiation optical system, and a monitor of surface states of the semiconductor wafer are synchronized with each other.  
     
     
       12. A surface state monitoring method comprising: applying infrared radiation to at least one of a plurality of semiconductor wafers held in a wafer cassette, detecting infrared radiation which has undergone multiple reflection in the semiconductor wafer and exited from the semiconductor wafer, and analyzing the detected infrared radiation to monitor surface states of the semiconductor wafer, 
       an infrared radiation optical system being controlled to apply infrared radiation sequentially to a different one of said plurality of semiconductor wafers, whereby surface states of said plurality of semiconductor wafers held in the wafer cassette are continuously monitored.  
     
     
       13. A surface state monitoring method according to  claim 12 , wherein 
       a control of the infrared radiation optical system and a monitor of surface states of the semiconductor wafer are synchronized with each other.  
     
     
       14. A surface state monitoring method comprising: 
       applying infrared radiation to respective at least two or more of a plurality of semiconductor wafers held in a wafer cassette;  
       collectively detecting infrared radiations which has undergone multiple reflection in the semiconductor wafers and exited from the semiconductor wafers, respectively; and  
       analyzing the detected infrared radiation to monitor surface states of the semiconductor wafers.  
     
     
       15. A surface state monitoring method according to  claim 14 , wherein 
       surface states of said plurality of semiconductor wafers held in the wafer cassette are collectively monitored.